Effect of the FABP3 and LEPR gene polymorphisms and expression levels on intramuscular fat (IMF) content and fat cover degree in pigs

Intensive breeding programs, designed to improve lean meat content in pigs, have considerably increased the amount of meat in carcass. It was influenced on poor meat quality and decrease of intramuscular fat (IMF) content. FABP3 and LEPR genes, which are associated with fatty acid metabolism, are regarded as candidate genes for carcass fatness traits in pigs. The objective of this study was to analyze FABP3 and LEPR genes polymorphisms and expression levels and their relationship with fatness parameters and IMF content of the most valuable cuts in carcass (m. longissimus dorsi and m. semimembranosus). The results obtained showed a significantly (P < 0.001) higher level of the FABP3 transcript in ham muscle compared to loin, whereas considerably higher (P < 0.001) expression of the LEPR gene was observed in loin. The IMF level was affected by FABP3 c.103C > T and c.1811G > C polymorphisms in ham muscle (P < 0.05) and by c.103C > T polymorphism in loin (P < 0.01). In addition, c.1811G > C polymorphism was associated with individual fatness traits of the loin and carcass (P < 0.05). The fat content of whole carcass and primary cuts was positively and highly (P < 0.01) correlated with the mRNA abundance of LEPR gene. Furthermore, the expression of FABP3 gene influenced IMF levels in both studied muscles (P < 0.01).